[Specifications] The step drill bit set includes five standard HSS step drill bits that can replace 50 individual drill bits. A drill bit can be used as a substitute for multiple drill bits to meet different needs. [Parameters] Double cutting blades and X-type openings design ensures a faster and smoother cutting, and 3-sided shank design prevents slip in drill chuck. It can automatically deburr holes while drilling to keep the drill bit clean. [Wide application] Provided with small pressure and the sets can cut through the wood, sheet metal, steel and other surfaces. Hard automatic center punch can mark the positioning hole to prevent the drill and the screw from sliding. [Material] Made of strong and durable high speed steel coated with titanium , high speed steel make it last longer than others, titanium coating ensure easily cut through steel sheets, aluminum sheets, copper plastic wood board and many other types of sheet metal with ease. Product size: aluminum box 15*11*4cm Delivery content: Aluminum box*1 1/4-1-3/8"*1 3/16-7/8"*1 1/4-3/4"*1 1/8-1/2"*1pc 3/16-1/2"*1